Quality of active TB case finding suboptimal nationally: study

by Rahul Devi

India’s Tuberculosis (TB) programme has been actively working towards finding cases of TB outside of healthcare settings among high-risk populations since 2017. Recently, a team led by the National Institute of Epidemiology (ICMR-NIE) in Chennai conducted a national-level analysis to assess the quality of this active case finding (ACF) initiative. The results of the study, commissioned by the Central TB Division, were published in the journal Global Health Action on September 21.

The analysis was based on ACF data from 657 districts. It was found that out of the recommended three ACF cycles each year, 98% of the districts undertook only one cycle. Furthermore, most districts were uncertain about what constituted an ACF cycle.

Dr. Hemant Deepak Shewade, a senior scientist at ICMR-NIE and the first author of the paper, explained that based on a study conducted in South Africa, two ACF cycles in a year seem to have additional benefits compared to one cycle. However, there is no evidence to suggest that three cycles are necessary.

The quality of ACF was measured using three indicators: screening at least 10% of the district population for TB, testing at least 4.75% of the screened individuals, and diagnosing at least 5% of those tested. Additionally, the number of individuals who need to be screened to diagnose one active TB case, known as the number needed to screen (NNS), should be less than 1,538.

The study found that the quality of ACF was suboptimal across the country in 2021. Not a single state met all the ACF quality indicator cutoffs or achieved an NNS below 1,538. At the national level, only 9.3% of the population were screened, 1% of the screened individuals were tested, and 3.7% of the tested individuals were diagnosed. The NNS was 2,824, significantly higher than the recommended threshold.

Mapping, which involves identifying all high-risk populations within a district, should be conducted before implementing ACF. However, the study revealed that mapping was only carried out in areas where ACF was conducted and not for the entire district. Dr. Shewade explained that comprehensive data on the number of high-risk populations in each district was not available, so they reported the extent of ACF among the total district population and compared it against a derived cutoff of 10%.

The study also found that states with high percentages of screening had low percentages of testing among the screened individuals, while states with low screening rates had higher levels of testing and diagnosis. Dr. Shewade suggests that quality ACF indicators for each state should be based on the TB epidemiology in that particular state.

One of the weakest indicators of ACF quality was the percentage of people tested among those who had been screened, especially in population-based screening. Dr. Shewade identified suboptimal sputum collection and transport, as well as the requirement for presumptive TB cases to visit testing facilities on their own, leading to attrition, as potential reasons for this issue.

The recommendations made in this study have the potential to guide India’s ACF guidelines for TB and improve the quality of ACF in the country. It is crucial to address the shortcomings revealed by the analysis and strengthen the ACF program to effectively identify and diagnose TB cases among high-risk populations.

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